FIG. 16A shows an example disclosed in Patent Document 1. In FIG. 16A, a movable body 100 is opposed to a stator 110. The stator 110 has an end surface equipped with a projection 120. The projection 120 is formed of rubber. When the stator 110 is magnetized, the movable body 100 is attracted by the stator 110. Thus, the movable body 100 moves in a direction shown by an arrow. Consequently, in the state shown in FIG. 16B, the projection 120 is urged onto an end surface of the movable body 100 and is elastically deformed in the axial direction. In this way, the projection 120 absorbs kinetic energy of the movable body 100.